In the course of speaking an individual utilizes a wide variety of phonemes (speech sounds) which make up the words and phrases of the particular language. When a phoneme is heard with its normal acoustic spectrum, a "normal" listener can perceive it as a sound of the language, and is able to perceive differences between it and misarticulations such as substitutions, distortions, omissions or additions. However, a person who speaks with defective articulation is used to hearing the defective phonemes and perceives his or her speech as "normal" rather than as defective. Thus, a person with defective speech is resistive to change. Such problems exist with people having a physical or learned speech impairment, sometimes associated with auditory perceptual difficulties, and also with pesons having foreign or social dialects.
Various attempts have been made to provide systems for the training (i.e., therapy) of persons having speech and hearing impairment. One such device is described in U.S. Pat. No. 3,920,903, issued to I. Bellier on Nov. 18, 1975. The application resulting in this patent had priority from an application filed in France in 1972.
In a related field, a patent was issued to T. D. Humphrey, et al., (U.S. Pat. No. 4,024,789) on May 24, 1977. This patent discloses a tone analysis system with visual display that can be used in teaching of music, for example.
In order to provide a more useful instrument, it is one object of the present invention to provide a speech therapy apparatus wherein the coustic spectra for each of the phonemes of normal speech are selectively filtered and amplified such that a user thereof can more readily detect differences between the sounds as spoken and the sounds that are considered normal for the spoken word.
It is another object of the present invention to provide a "user friendly" speech therapy apparatus which can be easily operated by a clinician or a client so that teaching and therap is substantially simplified.
It is another object of the present invention to provide a speech therapy device which is lightweight and highly portable such that it can be utilized in any desired environment and not only restricted to a clinical laboratory.
These and other objects of the present invention will become apparent upon a consideration of the accompanying drawings and a detailed description thereof.